I also converted the three files that had lots of noise to 'OGG' files with sampling rate of 44.1 KHz. The first of these now has a lot less noise, but it still is not good. The other two have just as much noise as before.

I then converted one of the really bad tracks to 'mp3'. There was no improvement. Still has lots of noise.

Without knowing the exact details, there are two types of "noise" you are likely to encounter. The first is overdriving a digital signal - if you have the volume too high so you get clipping on the waveforms, you will get all sorts of strange crackling etc - turn the volume down to eliminate the clipping. The second is the track was noisy to start with - do the tracks play clean in media player for example? If not, then you have noise as part of the track and it is very difficult to get rid of that. We have run into issues with some mp3 files in the past where they were corrupted and they would crash Proshow, but I have not seen that for a while. If the noise is ONLY present in Proshow, but not when you play the tracks in an external player, then I'm not sure what is happening since I have not experienced that issue. Without actually hearing one of the problem ones, it is tough to make a better guess.

Mike explained to me that the problem I was having was called "clipping". He said that with digital audio tracks, if the volume is too high, the amplitude of the waveform will actually drop from the maximum value down to zero, causing the sound to appear to have static in it.

The solution was simple. In "Timeline" view of the waveform for the audio track, click on the waveform, after which a blue rectangular "box" will appear around the waveform. Place the cursor over the top edge of the blue box, see that the cursor changes to two horizontal parallel lines, and then "grab" that line (by left-clicking on the mouse), and drag it down slightly so that the waveform no longer touches the top (and bottom) of the blue box.

Mike explained to me that the problem I was having was called "clipping". He said that with digital audio tracks, if the volume is too high, the amplitude of the waveform will actually drop from the maximum value down to zero, causing the sound to appear to have static in it.

The solution was simple. In "Timeline" view of the waveform for the audio track, click on the waveform, after which a blue rectangular "box" will appear around the waveform. Place the cursor over the top edge of the blue box, see that the cursor changes to two horizontal parallel lines, and then "grab" that line (by left-clicking on the mouse), and drag it down slightly so that the waveform no longer touches the top (and bottom) of the blue box.

After I did that, the clipping was gone.

Had the same problem, followed your solution here and no more static ! Thanks